1. Field of the Invention
The present invention relates to a color chart, a chart image data recording medium storing chart image data representative of a color chart, a profile producing method and a profile producing apparatus for producing a profile using a color chart and a profile producing program storage medium storing a profile producing program which causes a computer to operate as the profile producing apparatus when the profile producing program is incorporated into the computer.
2. Description of the Related Art
Hitherto, there is known a profile producing method and a profile producing apparatus for producing a profile defining an association between coordinates of a color space depending on a device such as a printer and a scanner for performing input and output of images and coordinates of a color space independent of the device, using a color chart in which color patches are arranged. For example, in a shop photographic print system in which an image of a photographic print is read by a scanner and fed to a computer in form of an original image, so that a copy of the original image is created on the computer and is outputted on the photographic print by a printer, the computer operates as the profile producing apparatus so that a profile suitable for the scanner and the printer is created in form of for example an LUT (Look Up Table). And a color conversion between the color space depending on the device and the color space independent of the device is applied to the original image in accordance with the profile, so that a color of the photographic print of the original is coincident with a color of the photographic print of the copy.
Hitherto, to create the profile, there are used a color chart referred to as IT8 for example and a lattice color chart in which color patches corresponding to lattice points on a predetermined lattice defined in a color space are arranged in a similar fashion to that of lattice points on the color space. Further, there is used a dedicated color chart according to a performance of a system and a device.
By the way, as recent network technology advances, a field of giving and taking image data between devices is expanded, and devices, which are connected to a certain system, are diversified. It is impossible to prepare all profiles of such diverse devices beforehand. Thus, it is desired to offer a profile producing apparatus and a color chart, which are high in general-purpose properties, capable of producing suitable profile meeting with those diverse devices. However, the above-mentioned dedicated color chart and a profile producing apparatus premising such a dedicated color chart are of course low in general-purpose properties.
It is needed for IT8 and a lattice color chart that all the patches of the color chart are read at the time of creation of a profile, as a general rule. However, the number of patches to be used in creation of a profile is different in accordance with a performance of a device. That is, in the event that a performance of a device is excellent, a profile is created in accordance with data in which a number of patches having a number of colors including fine color difference of colors is read, so that a profile, which is high in continuity, is obtained. On the other hand, in the event that a performance of a device is wrong, it is difficult to implement a faithful reproduction of a plurality of colors having fine color differences. Accordingly, in the event that a profile is created in accordance with data in which a number of patches having a number of colors including fine color difference of colors is read, the profile is low in continuity. In this case, it is rather higher in continuity that a profile is created in accordance with data in which a few number of patches having a few number of colors clear in color difference of colors is read. For this reason, IT8, the lattice color chart, and the profile producing apparatus premising those color charts cannot cope with a plurality of sorts of devices mutually greatly different in performance, and are low in general-purpose properties.
In view of the foregoing, it is an object of the present invention to provide a color chart which is high in general-purpose properties, a chart image data recording medium storing chart image data representative of such a color chart, a profile producing method and a profile producing apparatus for producing a profile using such a color chart and a profile producing program storage medium storing a profile producing program which causes a computer to operate as the profile producing apparatus when the profile producing program is incorporated into the computer.
To achieve the above-mentioned object, the present invention provides a first color chart comprising a plurality of patches in which colors of the plurality of patches are read in accordance with a patch reading order determined beforehand, said color chart including:
a first patch group comprising a plurality of patches each having a predetermined color; and
a second patch group comprising a plurality of patches having colors among said predetermined colors, said plurality of patches being read later than the patches constituting said first patch group in accordance with said patch reading order.
Colors of the patches of the second patch group are able to be approximately computed in accordance with an interpolation computation based on the colors of the patches of the first patch group. Thus, to meet a performance of a device, both the first patch group and the second patch group, or only the first patch group are read to be used for creation of a profile, and thereby enhancing general-purpose properties.
In the first color chart according to the present invention as mentioned above, it is preferable that said first patch group includes patches of saturated colors of red, green, blue, cyan, magenta, yellow, white and black.
Since those saturated colors are colors corresponding to corners of the general color space, it is difficult to compute those saturated colors in accordance with an interpolation computation based on other colors.
Further, in the first color chart according to the present invention as mentioned above, it is preferable that patches, which belong to either one of said first patch group and said second patch group, occupy over half in its entirety.
This feature makes it possible to enhance effects of the present invention.
Furthermore, in the first color chart according to the present invention as mentioned above, it is preferable that same gray patches are disposed at a plurality of places.
The same gray patches disposed at a plurality of places are sensitive to input and output performance of colors by devices. Thus, this feature makes it possible to verify a performance of a device. Further, an arrangement of the same gray patches together with the first patch group and said second patch group makes it possible to know a performance of a device at the time of creation of a profile.
To achieve the above-mentioned object, the present invention provides a second color chart comprising a plurality of chart sheets which are sequentially read in accordance with a sheet reading order determined beforehand, said color chart comprising:
a faster-read sheet in which a plurality of patches each having a predetermined color are arranged, said faster-read sheet being relatively faster read in accordance with said sheet reading order; and
a later-read sheet in which a plurality of patches having colors among said predetermined colors are arranged, said later-read sheet being relatively later read in accordance with said sheet reading order.
Colors of patches of the later-read sheet can be approximately computed in accordance with an interpolation computation based on the colors of the patches of the faster-read sheet. Thus, it is possible to create a profile through reading the chart sheets by the necessary number of sheets to meet a performance of a device.
In the second color chart according to the present invention as mentioned above, it is preferable that in at least one of said plurality of chart sheets, same gray patches are disposed at a plurality of places.
Further, in the second color chart according to the present invention as mentioned above, it is preferable that in said plurality of chart sheets, same gray patches are disposed at common places of the chart sheets.
When colors of those gray patches are read, it is possible to verify a stability in an in-plane direction of input and output of colors of devices or a stability on an elapse basis.
In the color chart of the present invention, it is preferable that patches having relatively high saturation of colors are arranged outside more than patches having relatively low saturation of colors.
In general, colors lower in saturation are more easily affected by a disturbance of a performance of a device. A disturbance of a performance of a device is smaller with the more in the vicinity of the center. Thus, the patches having relatively lower color in saturation are disposed at the center, and patches having relatively higher color in saturation are disposed more outside as compared with patches having relatively lower color in saturation. This feature makes it possible to suppress an influence of a disturbance of a performance of a device.
Further, in the color chart of the present invention, it is preferable that said color chart includes patches each having a specific color for accuracy verification.
This feature makes it possible to verify the accuracy of a profile under conditions at the time of creation of a profile, and thus it is possible to accurately know the accuracy of a profile.
To achieve the above-mentioned object, the present invention provides a first chart image data recording medium storing chart image data representative of a color chart comprising a plurality of patches in which colors of the plurality of patches are read in accordance with a patch reading order determined beforehand, said color chart including:
a first patch group comprising a plurality of patches each having a predetermined color; and
a second patch group comprising a plurality of patches having colors among said predetermined colors, said plurality of patches being read later than the patches constituting said first patch group in accordance with said patch reading order.
To achieve the above-mentioned object, the present invention provides a second chart image data recording medium storing chart image data representative of a color chart comprising a plurality of chart sheets which are sequentially read in accordance with a sheet reading order determined beforehand, said color chart comprising:
a faster-read sheet in which a plurality of patches each having a predetermined color are arranged, said faster-read sheet being relatively faster read in accordance with said sheet reading order; and
a later-read sheet in which a plurality of patches having colors among said predetermined colors are arranged, said later-read sheet being relatively later read in accordance with said sheet reading order.
To achieve the above-mentioned object, the present invention provides a first profile producing apparatus comprising:
a data obtaining section for obtaining read data in which patches, constituting a color chart comprising a plurality of patches in which colors of the plurality of patches are read in accordance with a patch reading order determined beforehand, are read in accordance with the patch reading order, said color chart including a first patch group comprising a plurality of patches each having a predetermined color, and a second patch group comprising a plurality of patches having colors among said predetermined colors, said plurality of patches being read later than the patches constituting said first patch group in accordance with said patch reading order; and
a profile producing section for producing a profile defining an association between coordinate points on a color space depending on a device performing at least one of input and output of an color image and coordinate points on a color space independent of said device in accordance with the read data obtained by said data obtaining section.
To achieve the above-mentioned object, the present invention provides a second profile producing apparatus comprising:
a data obtaining section for obtaining read data in which at least one of chart sheets constituting a color chart comprising a plurality of chart sheets which are sequentially read in accordance with a sheet reading order determined beforehand, is read in accordance with the sheet reading order, said color chart comprising a faster-read sheet in which a plurality of patches each having a predetermined color are arranged, said faster-read sheet being relatively faster read in accordance with said sheet reading order, and a later-read sheet in which a plurality of patches having colors among said predetermined colors are arranged, said later-read sheet being relatively later read in accordance with said sheet reading order; and
a profile producing section for producing a profile defining an association between coordinate points on a color space depending on a device performing at least one of input and output of an color image and coordinate points on a color space independent of said device in accordance with the read data obtained by said data obtaining section.
According to the profile producing apparatus according to the present invention, it is possible to create a profile in accordance with read data in which the color chart of the present invention is read, and thereby enhancing general-purpose properties.
In the second profile producing apparatus according to the present invention as mentioned above, it is preferable that said data obtaining section obtains the read data by a corresponding number of the chart sheets based on a performance of said device.
When a profile is created through obtaining the read data by a corresponding number of the chart sheets based on a performance of said device, obtaining of the useless read data is avoided, and it is possible to create a great accuracy of profile in accordance with the suitable read data.
Further, in second profile producing apparatus according to the present invention as mentioned above, it is preferable that said data obtaining section obtains the read data one by one corresponding of the chart sheets in accordance with the said sheet reading order, and said data obtaining section judges whether a subsequent chart sheet of read data is to be obtained, and when it is decided that the subsequent chart sheet of read data is to be obtained, said data obtaining section obtains a subsequent chart sheet of read data.
For example, in the event that it is difficult to suitably determine the number of chart sheets beforehand, the data obtaining section obtains the read data one by one corresponding of the chart sheets, and the data obtaining section judges whether a subsequent chart sheet of read data is to be obtained, in accordance with the obtained data and the created profile, so that the read data is suitably obtained.
To achieve the above-mentioned object, the present invention provides a first profile producing method comprising:
a data obtaining step of obtaining read data in which patches, constituting a color chart comprising a plurality of patches in which colors of the plurality of patches are read in accordance with a patch reading order determined beforehand, are read in accordance with the patch reading order, said color chart including a first patch group comprising a plurality of patches each having a predetermined color, and a second patch group comprising a plurality of patches having colors among said predetermined colors, said plurality of patches being read later than the patches constituting said first patch group in accordance with said patch reading order; and
a profile producing step of producing a profile defining an association between coordinate points on a color space depending on a device performing at least one of input and output of an color image and coordinate points on a color space independent of said device in accordance with the read data obtained by said data obtaining section.
To achieve the above-mentioned object, the present invention provides a second profile producing method comprising:
a data obtaining step of obtaining read data in which at least one of chart sheets constituting a color chart comprising a plurality of chart sheets which are sequentially read in accordance with a sheet reading order determined beforehand, is read in accordance with the sheet reading order, said color chart comprising a faster-read sheet in which a plurality of patches each having a predetermined color are arranged, said faster-read sheet being relatively faster read in accordance with said sheet reading order, and a later-read sheet in which a plurality of patches having colors among said predetermined colors are arranged, said later-read sheet being relatively later read in accordance with said sheet reading order; and
a profile producing step of producing a profile defining an association between coordinate points on a color space depending on a device performing at least one of input and output of an color image and coordinate points on a color space independent of said device in accordance with the read data obtained by said data obtaining section.
To achieve the above-mentioned object, the present invention provides a profile producing program storage medium storing a profile producing program, which causes a computer to serve as the profile producing apparatus comprising the data obtaining section and the profile producing section, as mentioned above, when said profile producing program storage medium is incorporated into said computer.
Incidentally, with respect to the profile producing program and the profile producing method, there are merely shown only the basic embodiments. However, the profile producing program and the profile producing method are not restricted to the basic embodiments as mentioned above, and include various modifications associated with the embodiments of the profile producing apparatus as mentioned above.